Different types of pool cleaning robots exist, and particularly known are cleaning robots whose suction is connected to the suction device of the pool filtration system and depends on the latter, and cleaning robots equipped with a pump that is independent in relation to the pool filtration system.
A robot that uses the filtration system of the pool is disclosed for example in US patent application US2009/307854. A robot that is equipped with a pump and has an internal filtration system is disclosed for example in US patent application US2007/028405.
There is also one example of a pool cleaning robot that is marketed under the name WEDA B680. This robot has an internal pump and a filter bag which is connectable to its impeller outlet. This robot can also be connected to an external filtration system such as the filtration system of the pool by removing the filter bag, and directing the impeller outlet to be filtered by the external filtration system.